1. Field of the Invention
The present invention relates to a system for driving a liquid crystal display, and particularly to a system for increasing LCD response time.
2. Description of the Related Art
The slow electro-optical LCD response time panels has been a major roadblock for the LCD market to expand beyond notebook and computer monitors. Although there has been significant progress in enhancing the switching speed of nematic liquid crystals (LCs), visual artifacts resulting from slow response are still quite noticeable. The full on/off time may be adequate, but response time between intermediate grays is inherently slow; up to 10 times as slow as the full on/off time.
Synthesizing even faster LC molecules is one obvious solution, however, expense and time are both considerable, since the speed must increase by as much as three times, There is a need for a method utilizing large voltage to drive liquid crystals to reduce response time.
FIG. 1 shows a conventional driving method of increasing LCD response time. The method utilizes the concept of data-overwrite realized by applying large voltage across liquid crystals to reduce response time. As shown in FIG. 1, a data driver pulls the voltage level Cn−1 of the n−1 frame to the voltage level Cn, wherein Cn−1, Cn, and Cn′ all represent voltages corresponding to specific gray levels. For a data driver not applied in data-overdriven method, a voltage level is Cn and the trace T1 shows a charging process of liquid crystals. For a data driver applied in data-overdriven method, a voltage level is Cn′ higher than voltage level Cn and the trace T2 shows a charging process of liquid crystals. When liquid crystals are charged to the voltage level Cn, the data driver drives the voltage level Cn′ to the voltage level Cn.
Because conventional data-overdrive mode is realized by switching image codes thereby changing voltage levels, there are limits to the highest and lowest image codes. There is thus a need for a novel method to realize data-overdriven.